Integrated circuits (IC), and the like, use various components and structures to interconnect (e.g., power, ground, signals, data, etc.) with other ICs, carriers, printed circuit boards (PCB) and components, and so forth. For example, connections may be made using contact pads, sockets or terminals, wire bonds, and other components. In the case of “flip chips,” interconnects are often solder bumps or metallic posts protruding from a surface of the chip package.
As IC chip technology matures, smaller packages are possible due to smaller and denser ICs. Finer pitch interconnects are desirable to connect smaller chip packages and components to each other and to other carriers, PCBs, and the like. Taller interconnects are desirable for maintaining regular manufacturing processes (such as reflow and underfill processes), as well as to improve solder joint reliability. Further, taller interconnects are also desirable for coupling packages on packages, chips to chips, and other stacked system arrangements.
Some solutions have been advanced to achieve taller interconnects, with some of the solutions having a fine pitch. For example, copper pillars with a desired height may be coupled to silicon chips. Providing the copper pillars can involve plating a silicon surface repeatedly to achieve the desired height. However, this can be an expensive process, and can often take about 4 hours to plate a 40-50 um pillar on a silicon die. In another example, copper-to-copper bonding can also be used to obtain a fine pitch interconnect for chip to chip coupling. However, a very high level of chip to chip co-planarity (which can be difficult and/or expensive to achieve) is needed for a successful and lasting bond.